| 摘要 |
Provided is a speed change head, comprising a long gear rod (2), a short gear rod (12) and a gear speed change mechanism; a first end of the long gear rod is provided with a long rod inner hole (2-1) connectable to a tool bit, and a second end is provided with long rod external teeth (2-3); a first end of the short gear rod is connectable to a short rod connection (12-3) of a handle, and a second end is provided with short rod external teeth (12-2); and the gear speed change mechanism comprises a plurality of speed change gears (5, 6, 7) having large-diameter external teeth and small-diameter external teeth, the large-diameter external teeth (5-3, 6-3, 7-3) being engaged to the long rod external teeth of the long gear rod, and the small-diameter external teeth (5-2, 6-2, 7-2) being engaged to the short rod external teeth of the short gear rod. Also provided is a screwdriver, comprising a handle, a rod and the tool bit, the rod is the above speed change head. The gear speed change mechanism can achieve speed change of the tool bit corresponding to the handle, thus improving speed for disassembling parts such as a screw and a nut. |
